It is notable that in spite of the potential importance of gene-environment interactions, only a portion of the studies of complex diseases have attempted to account for these effects to date. While there are methodological issues in the design and analysis of gene-environment effects, recently methods have been proposed to account for these interactions in GWA studies (38). Furthermore, inclusion of environmental covariates into analyses of data generated by GWA studies revealed associations with new genetic loci and their levels of statistical significance were increased compared to unadjusted analyses (39). Thus, accounting for genetic and environmental factors and their interactions may increase statistical power to detect true risk factors.
